Contoured track shoe for sealed track belts

ABSTRACT

By employing a contoured track wear shoe having its leading and trailing edge portions formed with an inwardly directed curvature or cant so such a track shoe will have a sealing interference fit with a cylindrical reinforced elastomer track belt having a plurality of flat track shoe sites permanently formed in the elastomer of its outer periphery, the ingress of soil and rock particles under these edges of the track shoe is prevented when the track belt is mounted on a circular pneumatic carcass or bladder of an earthmoving vehicle and employed in earthworking environments.

United States Patent [1 1 Beyers CONTOURED TRACK SHOE FOR SEALED TRACK BELTS Inventor: Marvin E. Beyers, Peoria, 111.

Assignee: Caterpillar Tractor Co., Peoria, 111.

Filed: Aug. 25, 1972 Appl. No.: 283,722

US. Cl. 305/38 Int. Cl B62d 55/24, B62d 55/28 Field of Search 152/184, 182, 180, 179,

References Cited UNITED STATES PATENTS Myers 305/38 Myers 305/37 Richards; 305/35 EB 11111 3,802,751 1 Apr. 9, 1974 2,332,313 10/1943 Galanot ..305/38 Primary E.raminer-Richard .1. Johnson Attorney, Agent, or Firm-Fryer, Tjensvold, Phillips & Lempio 57 ABSTRACT By employing a contoured track wear shoe having its leading and trailing edge portions formed with an inwardly directed curvature or cant so such a track shoe will have a sealing interference fit with a cylindrical reinforced elastomer track belt having a plurality of flat track shoe sites permanently formed in the elastomer of its outer periphery, the ingress of soil and rock particles under these edges of the track shoe is prevented when the track belt is mounted on a circular pnellrtlaticv aressa or bledderpfe e r hworms vehicle and employed in earthworking environments.

10 Claims, 3 Drawing Figures MENEU HR 9 I974 sum 2 or 2 j lllll SHOE FOR SEALED TRACK BACKGROUND OF THE INVENTION Track belt systems employ an elastomer flexiblebelt with a plurality of track shoes attached to the outer circular periphery of the belt, with the belt supported by a pneumatic carcass,' gives a tired vehicle increased traction, improved flotation and increased resistance to penetration of objects which can puncture the pneumatic support system. Such track belts are described in this assignees copending U.S. Pat. application Ser. No. 93,033, entitled Flexible Track Belts and filed on Nov. 27, I970. In an effort to seal out rock and soil particles beneath the track shoes which are circumferentially disposed around the cylindrical elastomer belt, the outer circular peripheral surface is modified to include-a plurality of flat track shoe sites which are permanently formed in its outer periphery to eliminate the gaps under the leading and trailing edges of the track'shoes mounted on the otherwise normally circular surface of the belt. In addition, a raised transverse rib or ridge of elastomer can be formed between these flat track shoe sites so they will abut against adjacent leading and trailing edges of adjacent track wear shoes and prevent the ingress of soiland rock particles between such edges.

While the above track shoe and belt arrangement eliminates the wedge-shaped gaps under the leading and trailing edge portions of a track shoe mounted on a circular surface of an elastomer belt with the ribs limiting the ingress of soil and rock particles between the adjacent edges of the track wear shoes, some ingress of these particles may occur in certain earth-working environments in which earthmoving vehicles are operated.

As the presence of soil and rock particles under the contiguous surfaces of the track wear shoe and elastomer belt can limit the service life of the track belt, it is an object of this invention to improve the sealing relationship between the individual track wear shoe and its associated flat track shoe site permanently formed in the circumference of a flexible elastomer belt.

SUMMARY OF THE INVENTION To accomplish the above object and obtain other advantages, a contoured track wear shoe for use with a cylindrical elastomer track belt having a central cylindrical inextensible reinforcing ply and a plurality of flat track shoe sites permanently formed in its outer periphery to accept track wear shoes, includes a track wear shoe having a top wear surface and a bottom mounting surface with the mounting surface having a leading edge surface portion and a trailing edge surface portion separated by a flat central surface portion wherein the leading and trailing edge surface portions are canted inwardly so that their outermost edge is higher than the plane of the flat central surface portion which will allow these edges to sealingly deform the elastomer of their associated flat track shoe site formed in the belt when the belt is clamped against the bottom mounting surface of the contoured shoe when the belt is supported about the circumference of a pneumatic carcass. Generally the cant or a cord of any curvature in these leading and trailing edge surface portions with respect to the plane of the flat central surface portion of the mounting surface is in the range of 3 degrees for a circular belt having 36 such contoured track wear shoes mounted thereon and a nominal diameter of approximately 88- /2 inches to avoid excessive stress concentration and undue deflection at the leading and trailing perimeters of the flat shoe site where the leading and trailing edge portions of the individual shoes engage the elastomer as the shoes pass through the footprint formed by the pneumatically supported system at which time these shoes articulate toward an aligned condition.

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the instant invention is obtained by reading this specification in light of the accompanying drawings wherein:

FIG. 1 is'a perspective of a contoured track wear shoe according to this invention;

FIG. 2 is an elevation of a track wear shoe shown in FIG. 1 and exploded from a portion of an associated elastomer belt which has parts broken away; and

FIG. 3 is a cross section through a track shoe shown in FIG. I mounted with an elastomer belt and illustrating how the track wear shoe is attached to the belt.

DESCRIPTION OF A PREFERRED EMBODIMENT In FIGS. 1 and 2, a general configuration of an improved rectangular track wear shoe 10 is illustrated in which the shoe has a top wear surface 11 having two spaced apart grousers 12 disposed thereon. These grousers are respectively located on a leading edge portion 13 and a trailing edge portion 14 of the shoe and are separated by a central portion 15, all of which portions are formed as integral parts of the shoe. It should be appreciated that the configuration of the grousers disclosed as being disposed transversely on the shoe could be changed and even replaced with rubber grousers with the appropriate modification to the top wear surface of the track wear shoe.

The bottom mounting surface 16 of the shoe 10 has the same three identifiable portions referred to above, and thus has surfaces corresponding thereto being respectively, the leading edge surface 13a, the trailing edge surface 14a, and the connecting central surface 15a. The connecting central surface 15a is flat and, in FIG. 2, is shown as being in a plane P which defines this flat transverse mounting surface which has a width A. By contrast, the leading edge surface 13a has a smaller width B which is the same width as the trailing edge surface 14a, that also has a width B. As can be seen in FIG. 2, the leading and trailing edge surfaces are canted relative to plane P so that these surfaces or a cord of these surfaces, if they are curved, make a small anglea with this plane. This angle is in the range of 1 per 25 inches of beltdiameter and may vary from 05 to 2 per 25 inches of nominal belt diameter for belts having diameters over 50 inches and from 2-6 per 25 inches of nominal belt diameter for belts having a diameter under 50 inches. To some extent, the degree of cant is dependent upon the total width of the track shoe and must be selected to avoid undue stress concentration and deformation of the belt directly under its leading and trailing edge surfaces as the pneumatically supported system'passes through the footprint. For example, a belt having a diameter of 88- /2 inches may include 36 of the contoured wear shoes, each 7 inches wide, wherein the flat mounting surface width A is 4 inches and the canted leading and trailing edge widths B are 1.5 inches. 4

Since the individual flat track shoe sites are permanently formed in the elastomer of the cylindrical elastomer belts, forming flat transverse sites thereon when the belt is supported on a circular carcass, the attachment of a contoured track wear shoe on a site will cause the leading and trailing edge portions of the mounting surface of the shoe to sealingly depress the elastomer thereunder. In order to avoid excessive wear of the elastomer along the outermost edges 13b and 14b of the individual wear shoes from the articulation of the shoes, these edges are rounded along the entire length L.

For a better appreciation of the invention, the cylindrical elastomer belt and its fabrication are described in greater detail. Basically, it consists of a cylindrical elastomer belt having at least one central inextensible cylindrical reinforcing ply 21 which is best illustrated in FIG. 3. This cylindrical reinforcing ply is usually formed by winding wire, cable, or similar inextensible reinforcingfilament about a constant diameter on a layer of uncured elastomer supported on a drum to form a plurality of loops arranged in a side-by-side relationship on the uncured elastomer. Thereafter a subse quent uncured layer of elastomer is applied over the reinforcing so that this cylindrical reinforcing ply will be completely encased in elastomer, and thereafter, a plurality of flat site-forming plates are forced against the outer periphery of the uncured belt which is then cured with these forming plates held against surface of the belt so that each is oriented parallel with the cord of the arcuate section that it replaces. As a result, a plurality of permanent flat track shoe sites 22 are formed circumferentially around the outer periphery of the elastomer belt, giving the belt a polygonal configuration. When fabricating the belt, it is preferable to add transverse strips of elastomer between the adjacent edges of the forming plates so that a transverse rib 23 is formed between the flat track shoe sites, as can be seen in FIG. 2. As the belt and forming plate assembly is usually fabricated on a supporting drum, it can be wrapped with A channel-shaped keeper bar 24 is used to attach each of the contoured track shoes 10 described above to the cylindrical elastomer belt 20. Each bar is preferably integrally formed with the belt by employing elastomer to fill the void between the circu'mferentiallyspaced keeper bars that are supported on the drum, which are then insulated with a layer of elastomer on which the reinforcing is subsequently wound. As a result of this fabrication, it can be appreciated that the individual keeper bars will be located beneath the reinforcing ply 21, as can be seen in FIG. 3. The actual attachment of each track wear shoe 10 iseffected with bolts 25, each of which pass through hole 17 in the outer ends of the track wear shoe, through a hole 26 in the associated ends of the keeper bars and into a threaded bore 27 of a retaining block 28, associated therewith. Tightening the bolts cinches the associated end of the keeper bar against the projecting end of the track shoe, as can be seen in FIG. 3.

The channel shape of the keeper bars 24 confines the elastomer of the belt from lateral extrusion when a bar keeper bar is approximately the same width as the flat central portion of the mounting surface 16 of each track shoe and therefore completely confines the belt in the central area of the track shoe to improve the elastomeric coupling between the reinforcing ply in the belt and the individual track shoe by increasing the rubber density about the wires so that little or no slippage will occur along the loops forming the reinforcing ply. The slight inward curvature of the leading and trailing edge portions of the contoured track shoe also aids in limiting the extrusion of the elastomer in a direction parallel to the circular reinforcing loops. Thus an improved attachment and sealing relationship are developed between the elastomer belt having the polygonal configuration and the contoured track shoe.

What is claimed is:

1. A contoured track wear shoe for employment on the outer surface of a flexible cylindrical'elastomer belt having a central cylindrical inextensible reinforcing ply on which belt the contoured track wear shoe is attached comprising:

a solid rectangular track shoe having a top wear surface and a bottom mounting surface, said wear surface having integral grouser means projecting therefrom and said mounting surface having a leading edge surface portion and a trailing edge surface portion connected by an integral flat central surface portion,-with said leading and trailing edge surface portions canted inwardly by a small angle no greater than 6 so their outermost edges are raised from a plane through said flat central surface portion so said leading and trailing edges will sealingly deform opposite sides of a flat elastomer belt surface when said central surface portion is clamped so it is contiguous therewith, said rectangular track shoe having attaching means at its projecting ends for attaching it to said belt.

2. The contoured track wear shoe defined in claim 1 wherein the outer peripheral edges of the leading and trailing edge portions are rounded along their length to prevent excessive wear of the flat elastomer belt surface to which the track wear shoe is attached.

3. The contoured wear shoe defined in claim 2 wherein the grouser means includes spaced apart grousers disposed on its wear surface.

4. The contoured wear shoe defined in claim 3 wherein the leading and trailing edge portions are approximately equal in width.

5. An improved track belt with contoured track wear shoes having a sealing interference fit therewith comprising:

a cylindrical elastomer belt having a cylindrical inextensible central reinforcing ply; said elastomer belt having a plurality of circumferentially disposed flat track shoe sites permanently formed in its outer peripheral surface; and

v a plurality of rectangular contoured track wear shoes with one track wear shoe associated with each flat track shoe site, each of said track shoes having a top wear surface and a bottom mounting surface, said bottom mounting surface portion having a leading edge surface portion and a trailing edge surface portion connected by an integral flat central surface portion, with said leading and trailing wherein each countoured track shoe is attached to the cylindrical elastomer belt with a channel shaped keeper bar which clamps said elastomer belt against the mounting surface of its associated contoured track shoe.

wherein the peripheral edges of the leading edge portion and the trailing edge portion are rounded and the cylindrical elastomer belt has a raised transverse rib between the flat track shoe sites which the rounded pe ripheral edges abut against when the contoured track shoe is attached to said cylindrical elastomer belt.

7. The improved track belt defined in claim 6 8. An elastomer track belt for mounting metal shoes circumferentially about a pneumatic carcass comprising:

a cylindrical elastomer belt having an internal cylindrical inextensible reinforcing ply surrounded by elastomer, said elastomer belt having a plurality of circumferentially disposed flat track shoe sites permanently formed in its outer peripheral surface;

a plurality of keeper means disposed circumferentially about the inner peripheral surface of said belt, said keeper means disposed inside said inextensible reinforcing ply with one of said keeper means located beneath each flat track shoe sites; and

a plurality of raised transverse ribs of elastomers located between adjacent flat track shoe sites, said transverse ribs integrally formed with said elastomer of said track belt and operable to form an edge seal between adjacent metal track shoes when the latter are mounted on adjacent flat track shoe sites whereby the ingress of foreign materials under the forward and trailing edges of said several metal track shoes is restricted by the resulting seal.

.9. The elastomer track belt as. defined in claim 8 wherein the keeper means are integrally formed with the belt and comprise a metal bar means extending transversely of the belt beneath the circumferential reinforcing ply having attaching means on the ends thereof projecting beyond the edges of the track belt.

filament about a substantially constant diameter in a helical manner. 

1. A contoured track wear shoe for employment on the outer surface of a flexible cylindrical elastomer belt having a central cylindrical inextensible reinforcing ply on which belt the contoured track wear shoe is attached comprising: a solid rectangular track shoe having a top wear surface and a bottom mounting surface, said wear surface having integral grouser means projecting therefrom and said mounting surface having a leading edge surface portion and a trailing edge surface portion connected by an integral flat central surface portion, with said leading and trailing edge surface portions canted inwardly by a small angle no greater than 6* so their outermost edges are raised from a plane through said flat central surface portion so said leading and trailing edges will sealingly deform opposite sides of a flat elastomer belt surface when said central surface portion is clamped so it is contiguous therewith, said rectangular track shoe having attaching means at its projecting ends for attaching it to said belt.
 2. The contoured track wear shoe defined in claim 1 wherein the outer peripheral edges of the leading and trailing edge portions are rounded along their length to prevent excessive wear of the flat elastomer belt surface to which the track wear shoe is attached.
 3. The contoured wear shoe defined in claim 2 wherein the grouser means includes spaced apart grousers disposed on its wear surface.
 4. The contoured wear shoe defined in claim 3 wherein the leading and trailing edge portions are approximately equal in width.
 5. An improved track belt with contoured track wear shoes having a sealing interference fit therewith comprising: a cylindrical elastomer belt having a cylindrical inextensible central reinforcing ply; said elastomer belt having a plurality of circumferentially disposed flat track shoe sites permanently formed in its outer peripheral surface; and a plurality of rectangular contoured track wear shoes with one track wear shoe associated with each flat track shoe site, each of said track shoes having a top wear surface and a bottom mounting surface, said bottom mounting surface portion having a leading edge surface portion and a trailing edge surface portion connected by an integral flat central surface portion, with said leading and trailing edge surface portions canted inwardly with reference to said central surface portion whereby said leading and trailing edge surface portions will sealingly deform opposite sides of said flat track shoe site when said central surface is contiguous with a central surface of said flat track shoe site.
 6. The improved track belt defined in claim 5 wherein the peripheral edges of the leading edge portion and the trailing edge portion are rounded and the cylindrical elastomer belt has a raised transverse rib between the flat track shoe sites which the rounded peripheral edges abut against when the contoured track shoe is attached to said cylindrical elastomer belt.
 7. The improved track belt defined in claim 6 wherein each countoured track shoe is attached to the cylindrical elastomer belt with a channel shaped keeper bar which clamps said elastomer belt against the mounting surface of its associated contoured track shoe.
 8. An elastomer track belt for mounting metal shoes circumferentially about a pneumatic carcass comprising: a cylindrical elastomer belt having an internal cylindrical inextensible reinforcing ply surrounded by elastomer, said elastomer belt having a plurality of circumferentially disposed flat track shoe sites permanently formed iN its outer peripheral surface; a plurality of keeper means disposed circumferentially about the inner peripheral surface of said belt, said keeper means disposed inside said inextensible reinforcing ply with one of said keeper means located beneath each flat track shoe sites; and a plurality of raised transverse ribs of elastomers located between adjacent flat track shoe sites, said transverse ribs integrally formed with said elastomer of said track belt and operable to form an edge seal between adjacent metal track shoes when the latter are mounted on adjacent flat track shoe sites whereby the ingress of foreign materials under the forward and trailing edges of said several metal track shoes is restricted by the resulting seal.
 9. The elastomer track belt as defined in claim 8 wherein the keeper means are integrally formed with the belt and comprise a metal bar means extending transversely of the belt beneath the circumferential reinforcing ply having attaching means on the ends thereof projecting beyond the edges of the track belt.
 10. The elastomer track belt defined in claim 8 wherein the plurality of keeper means is insulated from the inextensible circumferential reinforcing ply by elastomer in said belt and the said circumferential reinforcing ply is fabricated by winding inextensible reinforcing filament about a substantially constant diameter in a helical manner. 